Hospitals Prescribe Big Data to Track Doctors at Work

Marnie Baker, a pediatrician at California's MemorialCare Health System, has an easy manner and ready smile. Now, though, her job is to be the bearer of a serious and, for some of her colleagues, unwelcome message.

She's the voice of a program that digitally tracks their performance, informs them when they don't measure up—and cajoles them to improve.

MemorialCare is part of a movement by hospitals around the U.S. to change...